Semiconductor microfabrication employs a lithography process using a resist composition containing (meth)acrylic resin component having alicyclic hydrocarbon skeletal structure such as adamantyl group (for example, JPH04-39665-A, JPH05-346668-A, JPH07-234511-A, JPH10-319595-A, etc.).
In lithography, theoretically, the shorter the expose wavelength becomes, the higher the resolution can be made, as expressed by Rayleigh's diffraction limit formula. The wavelength of an exposure light source for lithography used in the manufacture of semiconductor devices has been shortened year by year as g line having a wavelength of 436 nm, i line having a wavelength of 365 nm, KrF excimer laser having a wavelength of 248 nm and ArF excimer laser having a wavelength of 193 nm. F2 excimer laser having a wavelength of 157 nm seems to be the next-generation exposure light source. Further, as the exposure light source of the subsequent generation, soft X ray (EUV) having a wavelength of 13 nm or shorter has been proposed as the exposure light source following the 157 nm-wavelength F2 excimer laser.
When light sources used for KrF excimer laser or those having shorter wave length are used, it is necessary to enhance the sensitivity of resists. Therefore, chemically amplified resists utilizing the catalytic action of an acid generated by exposure and containing a resin having a group being dissociated by the acid.
In lithography process utilizing such a shorter wavelength, improvement of pattern profiles has become important subject as line-widths become narrower (e.g. Proc. of SPIE Vol. 5038 (2003), 689-698).
Recently, it has been reported that resist composition with high transparency, good sensitivity and high resolution can be obtained when triphenylsulfonium 1-adamantylmethoxycarbonyldifluoromethansulfonate, p-tolyldiphenylsulfonium perfluorooctanesulfonate, and the like are used as an acid generator (e.g. JP2004-4561-A).